The need for making a stringed musical instrument compact in size for storage and travel has led to several inventions. Representative of the prior art are Jorgensen U.S. Pat. No. (4,073,211), Litwin U.S. Pat. No. (4,191,085), Fishman U.S. Pat. No. (4,911,057), Hoshino U.S. Pat. No. (4,939,970), and Stewart U.S. Pat. No. (5,353,672). Stewart defines well the shortcomings of the above listed prior art and teaches a collapsible guitar with a quick disconnect neck and submerged string tunnels. The invention of Stewart provides an entire guitar unit that is manufactured as collapsible. Unlike Stewart's, the present invention teaches a collapsible kit assembly that can modify any existing guitar, therefore musicians are allowed to modify their favorite instruments to make them collapsible and interchangeable with brand name guitars, and are not limited to the particular design or make of Stewart's. Stewart also teaches a neck plate assembly that functions with rail alignments. The present invention provides a neck and body plate assembly that incorporates tooling dowels and slip fit which provide for greater realignment accuracy of an SMI neck to an SMI body. Lastly, Stewart teaches a guitar that has both a cavity for storing the releasable guitar neck, and a plurality of string tunnels formed within said guitar body for eliminating the need for retuning after collapsing said guitar. Thus, Stewart's invention is clearly not designed for modifying existing guitars, rather it is a method for manufacturing new guitars or SMI units. The present invention is not near as complex as Stewart's, and provides a simple tension rack that is easily assembled and allows the user to maintain loosened guitar strings while folding a guitar neck over the guitar body to make it collapsible and compact.